A Novel Grating Lobe Suppression Method for Large-Spacing Phased Arrays Using Prephased Metalens and Limited Random Phase

The electronically steered phased array (ESPA), which is composed of periodic antenna elements, usually uses subarrays with large spacing to lower system complexity and cost. This kind of phased subarray (PSA) has a serious problem with grating lobes while beam scanning. A prephased metalens PSA (PMPSA) that combines prephases and metalens for modifying the transmitting phases is proposed. Further, the limited random phase method (LRPM) for randomizing the feeding phases and cooperating with prephased metalens to suppress the grating lobes is also proposed. In comparison to a PSA with the same parameters, the results demonstrate that the PMPSA can achieve a much better SLL, especially at wide scanning angles. Finally, calculated and simulated results show that a 16 × 16-unit phased array with 2 × 2-unit subarrays can achieve an SLL below −9.9 dB in 2D scanning using the limited random phase method.